Affinity chromatography using agarose-bound lectins will be used to obtain a purified preparation of erythropoietin. Cell separation techniques will be used to obtain a population of erythropoietin-responsive cell substantially free from contamination with myeloid and lymphoid precursors. With a pure hormone preparation and a specific target cell population studies will be carried out to investigate the relationship of DNA, RNA, and protein synthesis following exposure of the target cells to erythropoietin. In addition, the ability of androgenic steroids to influence these biochemical events will be investigated.